Download or read book Spin Structure of the Nucleon and Polarization written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spin Structure Of The Nucleon written by Bernard Frois and published by World Scientific. This book was released on 1998-02-24 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: From its early beginnings at SLAC in the 1970's, the study of nucleon spin structure using polarized lepton beams and polarized nucleon targets has become increasingly important in nuclear and particle physics, with current experiments at several of the world's high energy and nuclear physics laboratories (CERN, DESY, SLAC and Jefferson Lab) and with enormous related theoretical studies. The understanding of the fascinating but complicated problem of nucleon spin structure has progressed substantially, but fundamental questions remain and it can be confidently predicted that future activity will be high.The Erice Course on The Spin Structure of the Nucleon covered both the experimental and theoretical aspects of the subject, and this volume includes the lectures given at the School. In many cases the lecture material has been extended and updated by the authors. In addition, several recent publications on experimental work have been added in an appendix.
Download or read book Spin Structure of the Nucleon written by Erhard Steffens and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive survey of the most recent results from the field of quark-gluon structure of the nucleon, in particular how the spin of the nucleon is shared by its constituents. After very intriguing results from CERN and SLAC at the end of the 1980s, the last decade has seen a set of second-generation experiments at high energy accelerators that have yielded precise information on the solution of the 'Spin Crisis' - as well as opening up new questions. The articles are written by experts from the leading collaboration and theory groups as well as providing an expert summary of the state of the art, the book points the way to future research directions. Its main focus is on semi-inclusive and exclusive measurements of deep inelastic lepton scattering, which enables for the first time the determination of the flavor-separated quark spin distributions. Future developments on generalized parton distributions and their interpretation as well as the transverse spin structure are also covered. An indispensable volume for all working in hadronic physics.
Download or read book Internal Spin Structure Of The Nucleon Proceedings Of The Symposium written by Vernon W Hughes and published by World Scientific. This book was released on 1995-07-14 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topic of the internal spin structure of the nucleon has become an unusually active subfield of particle and nuclear physics, together with the relevant technologies. This volume presents up-to-date coverage.All the talks given at the symposium can be found in the volume. In addition, selected articles are reprinted, including two early papers which record initial thinking about the topic, all experimental papers giving data on nucleon spin structure functions determined from polarized lepton-nucleon scattering, and two valuable previously unpublished papers.
Download or read book Spin Structure Of The Nucleon Proceedings Of The The Riken Symposium written by Toshi-aki Shibata and published by World Scientific. This book was released on 1996-08-30 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: After about three decades of experimental and theoretical efforts, the structure of the nucleon (proton and neutron) is now fairly well understood based on quantum chromodynamics, but only if averaged over its spin. As the recent “proton spin crisis” revealed, we do not understand much about the nucleon structure when its spin is polarized to a specific orientation. We expect that our understanding on this challenging problem will soon be significantly improved by the RHIC-Spin and other experiments in the near future, as well as by the lattice- and perturbative-QCD theoretical calculations. The purpose of this symposium was to summarize the current understanding and discuss the future perspective of this problem with experimental and theoretical physicists from both high-energy and nuclear physics communities.The symposium covered the overview of the structure studies, updates on the experimental results from CERN, SLAC, DESY, FNAL, and KEK, future experiments at RHIC, and recent theoretical developments (18 presentations, 113 participants).
Download or read book The Spin Structure of the Nucleon written by Bernard Frois and published by World Scientific Publishing Company Incorporated. This book was released on 1997 with total page 685 pages. Available in PDF, EPUB and Kindle. Book excerpt: From its early beginnings at SLAC in the 1970's, the study of nucleon spin structure using polarized lepton beams and polarized nucleon targets has become increasingly important in nuclear and particle physics, with current experiments at several of the world's high energy laboratories (CERN, DESY and SLAC) and with enormous related theoretical studies. The understanding of the fascinating but complicated problem of nucleon spin structure has progressed substantially, but fundamental questions remain and it can be confidently predicted that future activity will be high. The Erice Course on The Spin Structure of the Nucleon covered both the experimental and theoretical aspects of the subject, and this volume includes the lectures given at the School. In many cases the lecture material has been extended and updated by the authors. In addition, several recent publications on experimental work have been added in an appendix.
Download or read book Spin Structure of the Nucleon Status and Recent Results written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: After the initial discovery of the so-called "spin crisis in the parton model" in the 1980s, a large set of polarization data in deep inelastic lepton-nucleon scattering was collected at labs like SLAC, DESY and CERN. More recently, new high precision data at large $x$ and in the resonance region have come from experiments at Jefferson Lab. These data, in combination with the earlier ones, allow us to study in detail the polarized parton densities, the $Q^2$ dependence of various moments of spin structure functions, the duality between deep inelastic and resonance data, and the nucleon structure in the valence quark region. Together with complementary data from HERMES, RHIC and COMPASS, we can put new limits on the flavor decomposition and the gluon contribution to the nucleon spin. In this report, we provide an overview of our present knowledge of the nucleon spin structure and give an outlook on future experiments. We focus in particular on the spin structure functions $g_
Download or read book Spin Structure of the Deuteron written by Nevzat Guler and published by LAP Lambert Academic Publishing. This book was released on 2013-01 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physics program with CLAS at Jefferson Lab has collected a large amount of data on the spin structure functions of the nucleon by using polarized electron beam directed on polarized NH3 and ND3 targets. In these experiments, the virtual photon asymmetry and the spin structure functions were measured with an unprecedented precision in a large kinematic range. The data help us to better understand the spin structure of the nucleon, especially in the transition region between hadronic and quark-gluon degrees of freedom. Therefore, it will be possible to put limits on quark-hadron duality, test pQCD predictions for the quark polarization at large Bjorken x, perform more precise calculations of higher-twist matrix elements in the framework of the Operator Product Expansion and get a glimpse of A1 at high x. In addition, using available proton and deuteron data together and utilizing a new unfolding technique, the spin structure functions for the neutron in the resonance region are extracted.
Download or read book Nucleon Spin Structure Functions G1 and G2 from Polarized Inclusive Scattering written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper will present a survey of recent experimental results for the g1 and g2 spin structure functions. Over the past decade, these structure functions (and the virtual photon asymmetries A1 and A2) have been well-measured in the large-Q2 scaling region using inclusive polarized deep-inelastic scattering. New precision results from Jefferson Lab are now becoming available which cover kinematic regions that were previously poorly measured or completely unmeasured. Topics covered will include: recent experiments at Jefferson Lab which have made precise measurements of g1 in the resonance region for both proton and neutron to investigate the Q2 evolution of the GDH sum rule, a new measurement of A1 for the neutron in the large-x region where valence quark dynamics dominate, new precision results for g2 from Jefferson Lab, a review of the g1 results and NLO analyses in the scaling region for the SLAC, HERMES, and SMC data. Finally, a survey of results expected from several new experime.
Download or read book Spin 96 Proceedings Of The 12th International Symposium On High energy Spin Physics written by J E J Oberski and published by World Scientific. This book was released on 1997-04-15 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments using highly polarized intense beams and targets, and theoretical studies of spin and polarization phenomena, are now providing us with numerous additional details of the electroweak and strong interactions and the structure of matter. The spin structure of the nucleon has been measured over wide ranges of kinematic variables, and the cross sections have been calculated to several orders in perturbative field theory. At present, the influence of the higher twist contributions, the gluon spin, and the quark orbital angular momentum are under scrutiny. Quantum chromodynamics (QCD) captures a lot of our experimental knowledge of hard polarized scattering processes. Can our understanding of such processes within QCD be further improved?Hyperons produced in high energy reactions show how puzzling strong interactions between hadrons still are. Spin observables in experiments at intermediate energy are used to test parity and charge symmetries. Will they also reveal, at low energy, a violation of time reversal symmetry? We are on the verge of using parity violation measurements at intermediate electron scattering energies to determine the amount of strange quark contributions to the neutral weak form factor of the nucleon. The polarization of the sea quarks is expected to be measured soon in W± decays produced in high energy polarized proton interactions. Will the jets in polarized Z⁰ decays show a definite handedness? These and many other topics are discussed in these proceedings.
Download or read book Understanding the Nucleon s Spin Structure written by Krzysztof Kurek and published by LAP Lambert Academic Publishing. This book was released on 2013 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern understanding of the nucleon's spin structure is presented. Polarisation dependent deep inelastic experiments have shown that the helicity contribution of quarks to the nucleon spin is much smaller than expected from the simple quark model. This observation and the role of the triangle anomaly lead to the conclusion that gluons - if strongly polarised, might solve the spin problem of the nucleon. Therefore a direct gluon polarisation measurement is the one of main goals of the COMPASS experiment spin physics programme. New results for the gluon polarisation are obtained. The results strongly support the hypothesis, that the gluons inside the nucleon are weakly or not polarised. Therefore, the possible importance of quark and gluon angular momenta are discussed. A short review of the nucleon's spin structure results obtained in a Lattice Quantum Chromodynamics approach is presented. The concept that the presence of the angular momentum of quarks inside nucleon is related to the spatial deformation of the quark densities in the transverse plane is also reviewed.
Download or read book Nucleon Spin Structure Functions from HERMES The First Year written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: HERMES, [und HE]RA[und Me]asurement of[und S]pin, is a second generation exper to study the spin structure of the nucleon by using polarized internal gas targets in the HERA 28 GeV electron storage ring. Scattered positrons and coincident hadrons are detected in an open geometry spectrometer which includes particle identification. Inclusive data with polarized[sup 3]He give the spin structure function[ital g[sup n][sub 1](x)] and the Ellis-Jaffe integral RR[Lambda]=[integral][sub 0][sup 1][ital g[sup n][sub 1](x)dx] for the neutron. The semi-inclusive spin asymmetries are a unique and sensitive probe of the flavor dependence of quark helicity distributions and properties of the quark sea. Data taken in 1995 with unpolarized hydrogen and deuterium targets provide measurements of the flavor distributions of sea and valence quarks. In a preliminary analysis, [Lambda][sup[ital n]][sub 1]= -0.032[+-]0. 013[sub[ital stat.]][+-] O.017[sub[ital syst.]] is obtained at Q[sup 2]= 3(GeV/c)[sup 2] for the Ellis-Jaffe integral.
Download or read book Symposium on the Internal Spin Structure of the Nucleon written by Vernon W. Hughes and published by World Scientific Publishing Company Incorporated. This book was released on 1995 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spin Structure of the Proton written by Steven D. Bass and published by World Scientific. This book was released on 2008 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the main challenges in nuclear and particle physics in the last 20 years has been to understand how the proton's spin is built up from its quark and gluon constituents. Quark models generally predict that about 60% of the proton's spin should be carried by the spin of the quarks inside, whereas high energy scattering experiments have shown that the quark spin contribution is small - only about 30%. This result has been the underlying motivation for about 1000 theoretical papers and a global program of dedicated spin experiments at BNL, CERN, DESY and Jefferson Laboratory to map the individual quark and gluon angular momentum contributions to the proton's spin, which are now yielding exciting results. This book gives an overview of the present status of the field: what is new in the data and what can be expected in the next few years. The emphasis is on the main physical ideas and the interpretation of spin data. The interface between QCD spin physics and the famous axial U(1) problem of QCD (eta and etaprime meson physics) is also highlighted. Book jacket.
Download or read book Spin Structure at Long Distance written by Jian-Ping Chen and published by AIP Conference Proceedings (Nu. This book was released on 2009-08-04 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical developments -- Experimental developments -- Future experiments and active analyses.
Download or read book The Generalized GDH Sum Rule and the Spin Structure of the Neutron written by Jin Yuan and published by . This book was released on 2008 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleon spin structure has been of great interest since the CERN SMC experiment found that quarks carry only a small fraction of the nucleon spin. Since naively quarks are expected to carry most of the nucleon's spin, this observation became known as spin crisis. The availability of polarized beams and targets since the late 1970's has allowed the measurement of the nucleon spin structure functions, and furthermore checks of Quantum Chromodynamics (QCD), the theory of strong interactions, in its perturbative regime. Sum rules involving the spin structure of the nucleon offer an important opportunity to study QCD. It has recently been shown that the GDH sum rule and Bjorken sum rule are both special examples of a more general sum rule that applies to polarized electron scattering off nucleons. This generalized sum rule applies at all Q2. By studying the Q2 evolution of the extended GDH sum, one learns about the transition from quark-like behavior at high Q2, larger than 1 GeV2, to hadronic-like behavior at low Q2, close to 0. The transition between these two regimes is far from understood; it is a key issue in our understanding of the strong interaction. During mid 2003, we measured inclusive polarized cross sections in the scattering of high energy polarized electrons off the Jefferson Lab Hall A polarized 3He target. A strained GaAs photocathode was utilized in the polarized electron gun to provide an electron beam with a polarization of 70%. The high density polarized 3He target, based on optical pumping of rubidium and spin echange, was used as an effective neutron target. The polarization of the target was maintained at about 40% at beam currents as high as 15 muA. The target polarization was measured by Nuclear Magnetic Resonance methods calibrated using two independent techniques: proton thermal polarization (water calibration) and Electron Paramagnetic Resonance (EPR). The relative uncertainty on the target polarization was better than 4%. The target was operated with both longitudinal and transverse target spin orientations. In Jlab Hall A, in order to reach very low Q2 in experiment E97-110, a new septum magnet was used to make very small scattering angle measurements with the Hall A right spectrometer. The left spectrometer was used without a septum to monitor an unpolarized carbon target, downstream of the polarized 3He target, to check for possible false asymmetries. A wide range of data were measured: beam energies from 1.15 to 4.40 GeV were used at scattering angles of 6 and 9 degrees. The invariant mass W ranged across the resonance region, from inelastic threhold to the beginning of the deep inleastic region (W = 2 GeV). From the measured spin-dependent cross sections we extract the 3He spin structure functions g_{1} and g_{2}. Finally, we determined the extended GDH sum and other quantities for the Q2 range between 0.04 and 0.3 GeV2. The range of data allows extrapolation to the real photon point, studying the convergence of the sum rule, determining the slope of GDH sum rule as Q2 to 0 to check Chiral Perturbation Theory, and overlap with the previous higher Q2 experiment E94-010.
Download or read book An Overview of Recent Nucleon Spin Structure Measurements at Jefferson Lab written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Jefferson Lab have made significant contributions to improve our knowledge of the longitudinal spin structure by measuring polarized structure functions, g1 and g2, down to Q2 = 0.02 GeV2. The low Q2 data is especially useful in testing the Chiral Perturbation theory (cPT) calculations. The spin-dependent sum rules and the spin polarizabilities, constructed from the moments of g1 and g2, provide an important tool to study the longitudinal spin structure. We will present an overview of the experimental program to measure these structure functions at Jefferson Lab, and present some recent results on the neutron polarizabilities, proton g1 at low Q2, and proton and neutron d2 measurement. In addition to this, we will discuss the transverse spin structure of the nucleon which can be accessed using chiral-odd transversity distribution (h1), and show some results from measurements done on polarized 3He target in Hall A.
